Europe. Opposed realities, same currency

When the euro was born in the late 90's everybody (except for the UK and Sweden) thought that adopting it was the best way to boost the European Union (EU), to establish it as a competing power to the supremacy of the United States and its reference currency, the US Dollar. It was expected to facilitate intra-EU commerce and tourism, ease the access to credit and financial instruments and making them more stable at the same time. Purchasing power and exports-imports from EU companies would benefit from having a better reference instrument to compare their money against the rest of the world currencies, lowering the risk introduced by exchange rates fluctuation worldwide. It really had all of those benefits, at least at the beginning...